ABSTRACT
Exogenous quorum sensing (QS) molecular can regulate the activity and granulation process of anaerobic sludge in anaerobic digestion process, but would be impractical as a standalone operation. Here we demonstrated that application of 1 mg L-1 boric acid assisted in an upflow anaerobic sludge blanket (UASB) reactor recovery from volatile fatty acids (VFAs) accumulation. After VFAs accumulation, the chemical oxygen demand (COD) removal suddenly reduced from 78.98% to 55.86%. The relative abundance of acetoclastic methanogens decreased from 55.79% to 68.28%-23.14%â¼25.41%, and lead to the acetate accumulate as high as 1317.03 mg L-1. Granular sludge disintegrated and the average size of sludge decreased to 586.38 ± 42.45 µm. Application of 1 mg L-1 boric acid activated the interspecies QS signal (AI-2) and then induced the secretion of intraspecies QS signal (N-acyl-homoserine lactones, AHLs). AHLs were then stimulated the growth of syntrophic acetate oxidizing bacteria and hydrogenotrophic methanogen. Moreover, the concentration of acetate decreased to 224.50 mgâ§L-1, and the COD removal increased to 75.10% after application of 1 mg L-1 boric acid. The activated AI-2 may induce multiple quorum-sensing circuits enhance the level of AI-2 and AHLs in parallel, and in turn assisted in anaerobic digestion recovery from VFAs accumulation.
Subject(s)
Bioreactors , Fatty Acids, Volatile , Quorum Sensing , Sewage , Fatty Acids, Volatile/metabolism , Anaerobiosis , Sewage/microbiology , Bioreactors/microbiology , Boron , Waste Disposal, Fluid/methods , Boric Acids/metabolism , Biological Oxygen Demand Analysis , Bacteria/metabolism , Acyl-Butyrolactones/metabolismABSTRACT
BACKGROUND: Undifferentiated pleomorphic sarcoma (UPS) is a rare malignant mesenchymal tumor with a poor prognosis. It mainly occurs in the extremities, trunk, head and neck, and retroperitoneum regions. Owing to the lack of specific clinical manifestations and imaging features, UPS diagnosis mainly depends on pathological and immunohistochemical examinations for exclusive diagnosis. Here we report an extremely rare case of high-grade UPS in the common bile duct (CBD). There are limited available data on such cases. CASE SUMMARY: A 70-year-old woman was admitted to our department with yellow eyes and urine accompanied by upper abdominal distending pain for 2 wk. Her laboratory data suggested significantly elevated hepatorenal function levels. The imaging data revealed calculous cholecystitis, intrahepatic and extrahepatic bile duct dilation with extrahepatic bile duct calculi, and a space-occupying lesion at the distal CBD. After endoscopic biliary stenting and symptomatic support therapy, CBD exploration and biopsy were performed. The frozen section indicated malignant spindle cell tumor of the CBD mass, and further radical pancreaticoduodenectomy was performed. Finally, the neoplasm was diagnosed as a high-grade UPS combined with the light-microscopic morphology and immunohistochemical results. CONCLUSION: This extremely rare case highlighted the need for increasing physicians' vigilance, reducing the odds of misdiagnosis, and providing appropriate treatment strategies.
ABSTRACT
A novel promoter system for glycosylation is described. A catalytic amount of thiourea and Cu(OTf)2 together with a slight excess of N-iodosuccinimide synergistically promotes glycosylation at room temperature. The combination of reagents applies to some 2-azidoselenoglycoside and thioglycoside donors. A wide range of alcoholic acceptors underwent smooth conversion to O-(2-azido)glycosides with good stereoselectivities. In addition, the value of this method has been highlighted by its convenient operation and outstanding functional group compatibility.
ABSTRACT
Cronobacter sakazakii is an opportunistic foodborne pathogen that mainly infects infants and immunocompromised people, with a high mortality rate. However, the efficient transformation method of this bacterium has not been systematically reported. In this study, we developed a fast and efficient transformation method for C. sakazakii by cold sucrose treatment. Compared with CaCl2 or glycerol treatment, the transformation efficiency of this method is significantly high when bacteria were cultured overnight at 42°C before cold sucrose treatment. Furthermore, applying this method, we successfully knocked out the pppA gene by direct electroporation. Collectively, our study provides a simple, time-saving, and efficient method for competent cell preparation of C. sakazakii, which is conducive to the further research of C. sakazakii.
Subject(s)
Cronobacter sakazakii , Cronobacter , Infant , Humans , Cronobacter sakazakii/genetics , Immunocompromised Host , SucroseABSTRACT
Granulocytes play important roles in cancer, and their apoptotic status is often changed by the influence of tumor environment. However, the changes and the function on granulocyte apoptosis in cancer are unclear. In this study, we used tumor-bearing mouse model and tumor patients to analyzed the apoptosis of granulocytes in different tissues by flow analysis and TUNEL fluorescence staining, and found that the percentage of apoptosis cells in granulocytes was significantly decreased in late-stage tumor-bearing mouse and patients. The in vitro co-culture experiment showed that these antiapoptotic granulocytes could significantly inhibit T cell proliferation, and RNA-seq proved that there was obvious difference on the transcriptome between these cells and control cells, particularly immune-related genes. What is important, adoptive transfer of these antiapoptotic granulocytes promoted tumor progress in mouse model. Conclusively, we found that granulocytes in late-stage tumor could delay the process of apoptosis, inhibit T cell proliferation, and acquire pro-tumor activity, which provides a new therapeutic target for tumor immunity.
ABSTRACT
OBJECTIVE: We aimed to establish the reference range of thromboelastograph (TEG) maximum amplitude (MA) in patients taking antiplatelet drugs. METHODS: Between August 2015 and July 2018, a total of 4614 patients administrating with antiplatelet drugs (clopidogrel and aspirin) were retrospectively analyzed in this study. For MAA parameter, we used the 10th and 90th percentiles to establish a reference range. The Spearman correlation was used for the correlation analysis among the inhibition rate of adenosine diphosphate (ADP%) and MAADP , inhibition rate of arachidonic acid (AA%) and MAAA . Then, through receiver operating characteristic (ROC) curve analysis of the best cutoff point, the reference ranges of MAADP and MAAA could be deduced. Consistency evaluation was performed by statistical analysis of ADP% and MAADP , AA% and MAAA pairing for 4459 patients. RESULTS: The reference range of MAA was 8.1-25.8 mm. The reference range of MAADP was 19.8-43.2 mm, and the corresponding sensitivity of two endpoints was 0.796, 0.856 and specificity were 0.897, 0.904, respectively. The reference range of MAAA was 18.9-37.7 mm, and the corresponding sensitivity of two endpoints was 0.819, 0.829 and specificity were 0.922, 0.896, respectively. The inconsistency rate of ADP% and MAADP , and AA% and MAAA was 20.1% (898 cases) and 16.6% (738 cases), respectively. CONCLUSIONS: The reference range of MAADP and MAAA established by us were better in sensitivity and specificity. MAADP and MAAA were more accurate than conventional inhibition rate analysis in guidance of antiplatelet therapy, especially in patients with excessive low MA or high MAA .
Subject(s)
Platelet Aggregation Inhibitors/administration & dosage , Thrombelastography , Adult , Aged , Aged, 80 and over , Feasibility Studies , Female , Humans , Male , Middle Aged , ROC Curve , Reference ValuesABSTRACT
AIMS: Hereditary protein S (PS) deficiency is one of the natural anticoagulant deficiencies causing thrombophilia. We herein described a young male with recurrent deep venous thrombosis, who was diagnosed as type I PS deficiency with compound heterozygous mutations of PROS1 gene. We aimed to analyse the relationship between the genotype and phenotype detection and investigate the pathological mechanisms of PROS1 mutations causing PS deficiency. METHODS: Genetic analysis of PROS1 gene was carried out by direct sequencing. Thrombin generation potential and the inhibition function of thrombin generation by plasma PS were detected by thrombin generation test (TGT). The mRNA transcription level of mutant PS in vitro was measured by real-time PCR, while the protein level was evaluated by western blot and ELISA. Cellular distribution of the protein was further analysed by immunofluorescence. RESULTS: Compound heterozygous mutations (PROS1 c.1551_1552delinsG, p.Thr518Argfs*39 and PROS1 c.1681C>T, p.Arg561Trp) were identified in the propositus, and the former one was a novel small indel mutation. TGT results showed impaired inhibition of thrombin generation with the addition of activated protein C in his parents with certain heterozygous mutations. In vitro expression study, p.Thr518Argfs*39 mutant produced truncated protein retained in the cytoplasm, while p.Arg561Trp mutant partially affected the secretion of PS. Both mutations are located in C-terminal sex hormone-binding globulin (SHBG)-like domain of PS. CONCLUSIONS: Compound heterozygous mutations identified in the study have strong detrimental effect, causing severe type I PS deficiency in the propositus. SHBG-like domain of PS might play an important role in PS secretion system.
Subject(s)
Blood Coagulation/genetics , Blood Proteins/genetics , Heterozygote , Mutation , Protein S Deficiency/genetics , Venous Thrombosis/genetics , Adult , Blood Proteins/metabolism , Female , Genetic Predisposition to Disease , HEK293 Cells , Humans , Male , Middle Aged , Phenotype , Protein S , Protein S Deficiency/blood , Protein S Deficiency/diagnosis , Recurrence , Secretory Pathway , Severity of Illness Index , Thrombin/metabolism , Venous Thrombosis/blood , Venous Thrombosis/diagnosisABSTRACT
[This corrects the article DOI: 10.3389/fimmu.2018.01226.].
ABSTRACT
Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with no effective treatment. Cancer cells, especially cancer stem cells (CSCs), redirect immune cells to evade immune surveillance and even coopt these immune cells to support their growth and metastasis. However, the identification of CSCs and how CSCs interact with immune cells in PDAC remain uncharacterized. Here, we report that CD90 is expressed on both stromal and tumor cells and that high expression of CD90 is related to a poor prognosis in patients with PDAC. The CD90 highly expressed (CD90hi) population in PDAC cells harbors high stemness features and tumorigenicity. Notably, CD90 acts as an anchor for monocyte/macrophage adhesion, providing a physical interaction between CD90hi cells and monocytes/macrophages. In response, the crosstalk between CD90hi cells and monocytes/macrophages promotes immunosuppressive features of immune cells, which enhance the stemness and epithelial-mesenchymal transition (EMT) of PDAC cells. Moreover, PD-L1 is dominantly expressed in the CD90hi population, providing another strategy for these cells to evade immune surveillance. These findings provide an understanding of the biological significance of CD90 expression in PDAC cells and uncover a novel mechanism for how "stem-like" PDAC cells evade immune surveillance.
Subject(s)
Carcinoma, Pancreatic Ductal/immunology , Neoplastic Stem Cells/immunology , Pancreatic Neoplasms/immunology , Thy-1 Antigens/immunology , Animals , B7-H1 Antigen/biosynthesis , B7-H1 Antigen/immunology , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Carcinoma, Pancreatic Ductal/pathology , Cell Line, Tumor , Heterografts , Humans , Immune Tolerance , Macrophages/immunology , Mice , Mice, Nude , Monitoring, Immunologic , Monocytes/immunology , Pancreatic Neoplasms/pathology , Stromal Cells/immunology , Stromal Cells/pathology , Thy-1 Antigens/biosynthesisABSTRACT
Background Platelet-neutrophil aggregates (PNAs) are fundamental mechanisms linking hemostasis and inflammatory processes. Elevated level of PNAs have been reported in inflammatory diseases and coronary artery diseases. However, studies on the correlation between PNAs formation and deep venous thrombosis (DVT) are not available. Methods A total of 92 participants were involved in this study, including 32 cases with DVT and 60 cases without DVT. Blood samples coagulated by K2-EDTA or sodium citrate were prepared for blood cell count and blood smears. PNAs and platelet activation were measured using flow cytometry. The correlation between platelet activation level and PNAs level was analyzed by linear regression. Receiver operating characteristic (ROC) analysis was performed, assessing the prognostic performance of PNAs to predict potential risk of DVT occurrence. Results PNAs was found in the blood smears of patients with DVT. Significant increased level of PNAs was identified in DVT group (medium 8.43%, interquartile range [IQR] 4.11%-15.69%), compared with that in control group (5.16%, IQR 2.40-9.60, p<0.01). The DVT group also showed a dramatic elevated level of total platelet activation (medium 16.06%, IQR 6.04-22.05) vs. control group (11.26%, IQR 5.54-19.99, p<0.05). The PNAs level was correlated with total platelet activation (r2=0.58, p<0.0001). A significantly high odds ratio (OR) of DVT occurrence was identified when the level of PNAs was higher than 7.4% (OR 3.60, 95% confidence interval [CI] 1.463-8.838, p<0.01). Conclusions An elevated level of PNAs was associated with risk of DVT occurrence, which might be a suitable marker predicting DVT development.
Subject(s)
Blood Platelets/metabolism , Neutrophils/metabolism , Venous Thrombosis/blood , Venous Thrombosis/epidemiology , Aged , Blood Platelets/physiology , Cell Aggregation , Female , Humans , Male , Middle Aged , Platelet Activation/physiology , ROC Curve , Risk FactorsABSTRACT
Follicular helper T (Tfh) cells are the specialized CD4+ T cell subset that supports B cells to produce high-affinity antibodies and generate humoral memory. Not only is the function of Tfh cells instrumental to mount protect antibodies but also to support autoantibody production and promote systemic inflammation in autoimmune diseases. However, it remains unclear how the activation of Tfh cells is driven in autoimmune diseases. Here, we report that in patients with rheumatoid arthritis (RA), excessive generation of CXCR5+PD-1+ memory Tfh cells was observed and the frequency of memory Tfh cells correlated with disease activity score calculator for RA (DAS28). The differentiation of Tfh cells is dependent on signal transducer and activator of transcription 3 (STAT3), the key transcription factor downstream of cytokine signal pathways. A drastic increase of phosphorylated STAT3 (pSTAT3) in CD4+ T cells were detected in RA patients who also produced larger amounts of STAT3-stimulating cytokines, including IL-6, IL-21, IL-10, and leptin than those of healthy controls. Importantly, the phosphorylation status of STAT3 in CD4+ T cells positively correlated with the plasma concentration of IL-6 and the frequency of memory Tfh cells. This study reveals an IL-6-pSTAT3-Tfh immunoregulatory axis in the pathogenesis of RA and reinforces its candidature as biomarkers and targets for diagnosis and therapy.
Subject(s)
Arthritis, Rheumatoid/immunology , Arthritis, Rheumatoid/metabolism , Cell Differentiation/immunology , STAT3 Transcription Factor/metabolism , T-Lymphocytes, Helper-Inducer/immunology , T-Lymphocytes, Helper-Inducer/metabolism , Adolescent , Adult , Aged , Aged, 80 and over , Arthritis, Rheumatoid/pathology , Cytokines/metabolism , Female , Humans , Interleukin-6/metabolism , Lymphocyte Activation/immunology , Male , Middle Aged , Phosphorylation , Severity of Illness Index , Signal Transduction , T-Lymphocytes, Helper-Inducer/cytology , Young AdultABSTRACT
This corrects the article DOI: 10.1038/nature24042.
ABSTRACT
Under homeostatic conditions, animals use well-defined hypothalamic neural circuits to help maintain stable body weight, by integrating metabolic and hormonal signals from the periphery to balance food consumption and energy expenditure. In stressed or disease conditions, however, animals use alternative neuronal pathways to adapt to the metabolic challenges of altered energy demand. Recent studies have identified brain areas outside the hypothalamus that are activated under these 'non-homeostatic' conditions, but the molecular nature of the peripheral signals and brain-localized receptors that activate these circuits remains elusive. Here we identify glial cell-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) as a brainstem-restricted receptor for growth and differentiation factor 15 (GDF15). GDF15 regulates food intake, energy expenditure and body weight in response to metabolic and toxin-induced stresses; we show that Gfral knockout mice are hyperphagic under stressed conditions and are resistant to chemotherapy-induced anorexia and body weight loss. GDF15 activates GFRAL-expressing neurons localized exclusively in the area postrema and nucleus tractus solitarius of the mouse brainstem. It then triggers the activation of neurons localized within the parabrachial nucleus and central amygdala, which constitute part of the 'emergency circuit' that shapes feeding responses to stressful conditions. GDF15 levels increase in response to tissue stress and injury, and elevated levels are associated with body weight loss in numerous chronic human diseases. By isolating GFRAL as the receptor for GDF15-induced anorexia and weight loss, we identify a mechanistic basis for the non-homeostatic regulation of neural circuitry by a peripheral signal associated with tissue damage and stress. These findings provide opportunities to develop therapeutic agents for the treatment of disorders with altered energy demand.
Subject(s)
Body Weight/physiology , Brain Stem/metabolism , Glial Cell Line-Derived Neurotrophic Factor Receptors/metabolism , Growth Differentiation Factor 15/metabolism , Animals , Brain Stem/cytology , Brain Stem/drug effects , Central Amygdaloid Nucleus/cytology , Central Amygdaloid Nucleus/physiology , Eating/physiology , Energy Metabolism/physiology , Feeding Behavior , Female , Glial Cell Line-Derived Neurotrophic Factor Receptors/deficiency , Glial Cell Line-Derived Neurotrophic Factor Receptors/genetics , Growth Differentiation Factor 15/genetics , Growth Differentiation Factor 15/pharmacology , Homeostasis , Male , Mice , Mice, Knockout , Neurons/drug effects , Neurons/metabolism , Parabrachial Nucleus/cytology , Parabrachial Nucleus/physiology , Stress, PsychologicalABSTRACT
Bladder cancer (BC) is one of the most commonly occurring cancers, with a high recurrence rate and poor outcomes in cases of relapsed metastatic disease. Here, we analyzed the markers and significance of myeloid-derived suppressor cells (MDSCs) for BC development and progression. MDSC markers were examined in peripheral blood from 113 BC patients and 20 healthy volunteers. We identified CD11b+CD33lowHLA-DR- CD3- cells as markers of MDSCs in peripheral blood from BC patients. We also demonstrated that MDSC numbers are higher in BC patients than healthy donors, and that MDSC numbers correlate with the clinical grade, stage, and poor prognosis. In addition, serum IL-6 levels are decreased in BC patients with higher MDSC counts. IL-6 blockade increases induction of MDSCs in vitro. Low IL-6 levels inhibit activation of Stat3, resulting in the increased formation of MDSCs in BC. These results indicate that the MDSCs numbers may serve as a novel prognostic marker in BC patients, and that targeting IL-6 signaling may be a promising strategy for BC treatment.
Subject(s)
Biomarkers, Tumor/blood , Carcinoma, Transitional Cell/pathology , Interleukin-6/blood , Myeloid-Derived Suppressor Cells/pathology , Urinary Bladder Neoplasms/pathology , Adult , Aged , Carcinoma, Transitional Cell/immunology , Carcinoma, Transitional Cell/mortality , Female , Humans , Interleukin-6/immunology , Kaplan-Meier Estimate , Male , Middle Aged , Myeloid-Derived Suppressor Cells/immunology , Prognosis , Urinary Bladder Neoplasms/immunology , Urinary Bladder Neoplasms/mortalityABSTRACT
To assess the basis of the different half-lives of long-acting human granulocyte colony-stimulating factor (G-CSF) drugs, the effect of neutrophil elastase on lipegfilgrastim and pegfilgrastim was investigated. Sensitivity to human neutrophil elastase (HNE) was evaluated by incubating the drugs with HNE followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Drugs were also incubated with isolated human neutrophils followed by Western blot analysis. Lipegfilgrastim was more resistant to degradation with HNE or neutrophils than pegfilgrastim and appeared more intact on SDS-PAGE gels and Western blots. Lipegfilgrastim retained more functional activity than pegfilgrastim after incubation with HNE (67% vs â¼ 9%, respectively) or neutrophils (80% vs â¼ 4%, respectively) as assessed in an NFS-60 cell-based [(3) H]-thymidine incorporation assay. The binding and affinity of untreated lipegfilgrastim and pegfilgrastim for G-CSF receptors were evaluated using an NFS-60 competitive G-CSF receptor-binding assay and surface plasmon resonance. Untreated drugs were also evaluated in the functional NFS-60 thymidine incorporation assay. G-CSF receptor binding, receptor affinity, and functional activity were comparable between untreated drugs. The results showed a greater resistance to neutrophil elastase degradation and concomitant retention of functional activity of lipegfilgrastim compared with pegfilgrastim, which potentially explains the clinical observations of a longer half-life of lipegfilgrastim versus pegfilgrastim.
Subject(s)
Granulocyte Colony-Stimulating Factor/metabolism , Granulocyte Colony-Stimulating Factor/pharmacokinetics , Leukocyte Elastase/metabolism , Filgrastim , Humans , Neutrophils/enzymology , Neutrophils/metabolism , Polyethylene Glycols , Recombinant Proteins/metabolism , Recombinant Proteins/pharmacokineticsABSTRACT
Appropriate packaging and condensation are critical for eukaryotic chromatin's accommodation and separation during cell division. Human vigilin, a multi-KH-domain nucleic acid-binding protein, is associated with alpha satellites of centromeres. DDP1, a vigilin's homolog, is implicated with chromatin condensation and segregation. The expression of vigilin was previously reported to elevate in highly proliferating tissues and increased in a subset of hepatocellular carcinoma patients. Other studies showed that vigilin interacts with CTCF, contributes to regulation of imprinted genes Igf2/H19, and colocalizes with HP1α on heterochromatic satellite 2 and ß-satellite repeats. These studies indicate that human vigilin might be involved in chromatin remodeling and regular cell growth. To investigate the potential role of human vigilin in cell cycle, the correlations between vigilin and chromosomal condensation and segregation were studied. Depletion of human vigilin by RNA interference in HepG2 cells resulted in chromosome undercondensation and various chromosomal defects during mitotic phase, including chromosome misalignments, lagging chromosomes, and chromosome bridges. Aberrant polyploid nucleus in telophase was also observed. Unlike the abnormal staining pattern of chromosomes, the shape of spindle was normal. Furthermore, the chromatin showed a greater sensitivity to MNase digestion. Collectively, our findings show that human vigilin apparently participates in chromatin condensation and segregation.
Subject(s)
Chromatin/drug effects , Chromosome Segregation/physiology , Chromosomes, Human/physiology , RNA-Binding Proteins/metabolism , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , Cell Cycle/genetics , Centromere/metabolism , Chromatin/metabolism , Chromobox Protein Homolog 5 , Chromosomes, Human/genetics , Hep G2 Cells , Humans , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , Mitosis/physiology , RNA Interference , RNA-Binding Proteins/antagonists & inhibitors , RNA-Binding Proteins/geneticsABSTRACT
An appropriate assessment strategy with validated anti-drug antibody (ADA) assays is critical for comparative evaluation of immunogenicity between a proposed biosimilar and its reference product. The strategy should aim to identify potential differences in immune responses between these products. While an ADA assay employing the proposed biosimilar product as the detecting reagent has been generally recommended for such evaluation, a product-specific assay using the product of interest may be of use as it offers a capability of detecting antibodies against specific epitopes from the respective product. Regardless of assay strategy, the performance of the assay must be fully assessed and method needs to be validated to meet the comparative purpose of immunogenicity assessment.
Subject(s)
Biosimilar Pharmaceuticals/pharmacology , Drug Discovery/methods , Immunity/drug effects , Animals , HumansABSTRACT
OBJECTIVE: To explore the effects of CCCTC-binding factor (CTCF) on human liver cancer stem cells (HepG2) and cell proliferation of HepG2 and Nasopharyngeal carcinoma cell line (CNE1). METHODS: The pEGFP-N1/CTCF, CTCF-shRNA and GFP-shRNA plasmids were constructed and transfected into HepG2 and CNE1 cells, and RT-PCR or Western blot were performed to detect the mRNA or protein levels of CTCF. The subpopulation of CD90+ cancer stem cells in HepG2 cells transfected with CTCF-shRNA plasmid or GFP-shRNA plasmid (as transfection control) were assayed by flow cytometry with the wild type HepG2 cells as control. Proliferation of cells transfected with CTCF-overexpression or CTCF-shRNA plasmid was evaluated by MTT assay. RESULTS: The levels of both mRNA and protein of CTCF were increased in pEGFP-N1/CTCF transfected HepG2 and CNE1 cells compared to that in pEGFP-N1 transfected cells (P < 0.05), and decreased in CTCF-shRNA transfected cells compared to that in cells transfected with GFP-shRNA (P < 0.05). The results of flow cytometry demonstrated that, detection rate of CD90+ cells in cells transfected with CTCF-shRNA plasmid [(1.7330 +/- 0.4177)%] was obviously higher than that of wild-type HepG2 cells [(0.5750 +/- 0.0629)%] and cells transfected with GFP-shRNA plasmid [(0.3500 +/- 0.0866)%] (P < 0.05). The results of MTT analysis showed that, alteration of CTCF had no effect on cancer cell proliferation (P > 0.05). CONCLUSION: CTCF inhibits human liver cancer stem cells but no effect on cell proliferation.
Subject(s)
Carcinoma, Hepatocellular/metabolism , Cell Proliferation , Liver Neoplasms/metabolism , Neoplastic Stem Cells/cytology , Repressor Proteins/metabolism , CCCTC-Binding Factor , Cell Line, Tumor , Flow Cytometry , Hep G2 Cells , Humans , Plasmids , RNA, Messenger , RNA, Small Interfering , TransfectionABSTRACT
CCCTC-binding factor (CTCF), a highly conserved zinc finger protein, is a master organizer of genome spatial organization and has multiple functions in gene regulation. Mounting evidence indicates that CTCF regulates the imprinted genes Igf2 and H19 by organizing chromatin at the Igf2/H19 locus, although the mechanism by which CTCF carries out this function is not fully understood. By yeast two-hybrid screening, we identified vigilin, a multi-KH-domain protein, as a new partner of CTCF. Subsequent coimmunoprecipitation and glutathione S-transferase pulldown experiments confirmed that vigilin interacts with CTCF. Moreover, vigilin is present at several known CTCF target sites, such as the promoter regions of c-myc and BRCA1, the locus control region of ß-globin, and several regions within the Igf2/H19 locus. In vivo depletion of vigilin did not affect CTCF binding; however, knockdown of CTCF reduced vigilin binding to the H19 imprinting control region. Furthermore, ectopic expression of vigilin significantly downregulated Igf2 and upregulated H19, whereas depletion of vigilin upregulated Igf2 and downregulated H19, in HepG2, CNE1 and HeLa cells. These results reveal the functional relevance of vigilin and CTCF, and show that the CTCF-vigilin complex contributes to regulation of Igf2/H19.
Subject(s)
Genomic Imprinting , Insulin-Like Growth Factor II/genetics , RNA, Long Noncoding/genetics , RNA-Binding Proteins/metabolism , Repressor Proteins/metabolism , Base Sequence , CCCTC-Binding Factor , Cell Line, Tumor , DNA Primers , Gene Expression Regulation , Humans , Protein Binding , RNA Interference , Reverse Transcriptase Polymerase Chain Reaction , Two-Hybrid System TechniquesABSTRACT
CCCTC-binding factor (CTCF) has been implicated in numerous aspects of chromosome biology, and vigilin, a multi-KH-domain protein, participates in heterochromatin formation and chromosome segregation. We previously showed that CTCF interacts with vigilin. Here, we show that human vigilin, but not CTCF, colocalizes with HP1α on heterochromatic satellite 2 and ß-satellite repeats. CTCF up-regulates the transcription of satellite 2, while vigilin down-regulates it. Vigilin depletion or CTCF overexpression reduces the binding of HP1α on the satellite 2 locus. Furthermore, overexpression of CTCF resists the loading of vigilin onto the satellite 2 locus. Thus CTCF may regulate vigilin behavior and thus indirectly influence the binding of HP1α to the satellite 2 locus.